Operating mechanism for high lift devices for airplanes



March 28, 1950 H. w. EARHART 2,502,315

OPERATING MECHANISM FOR HIGH LIFT DEVICES FOR AIRPLANES Filed Feb. 26, 1946 745%010 a lay/Wm??- INVENTOR.

Arm/ma k Patented Mar. 28, 1950 OPERATING MECHANISM FOR HIGH LIFT DEVICES FOR AIRPLANES I Harold W. Earhart, Wichita, Kans., assignor to Beech Aircraft Corporation, Wichita, Kans "a corporation of Delaware Application February 26, 1946, Serial No. 650,164

1 Claim. 1

The invention herein disclosed relates to mechanism for operating the high lift devices, or what are usually termed the flaps, of airplanes.

Objects'of the invention are to provide simple, inexpensive, practicaland reliable means for operatinga flap over any preselected path and rotating it through any desired angle at any selected rate of rotation, constant or varying;

' .Also. it is a purpose of the invention to enable the movement of the flap to be arrested at any point in the path of travel, at the corresponding angle of rotation for that point and to be held in that position without requiring additional means for looking it or the like.

A further special object of the invention is to obtain the effect of hinging the flap about a pointexternal to the wing contours and so oper ating it, without structure external to the contours.

Further objects are to provide mechanism having the advantages indicated and which can be readily built into existing and preferred designs of aircraft wing and flap constructions and "actuated by existing and accepted controls and part of the specification there is illustrated a present typical embodiment of the invention. Structure and arrangement, however, may be modified and changed as regards this illustration, all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawing is a broken sectional view of the controland operating mechanism as applied to an airplane wing, showing the flap in raised or closed position.

Fig. 2 is a similar view showing extended or lowered.

In the embodiment illustrated, a high lift device or flap 5 is mounted between end brackets, one of which is shown at 6, carried by the wing structure I.

These brackets are unique in that they each the flap fully carry a pair of cam tracks 8, 9, in this particular instance one in advance of, below and reversely camber-ed and inclined in respect to the other. Other relationships and arrangements are used for other designs.

In the illustration the forward track 8. is

shown as upwardly concave and as disposed below the front end of the rearward track and inclined from a high point directly beneath the forward end of the rear track, downwardly and forwardly to a position near the lower contour of the wing.

' The upper cam track 9 is shown downwardly "concave and as inclined downwardly from a point near the upper wing surface rearwardly to a point within the trailing edge of the wing. This upper track also is indicated as l'h'aving a downward break or drop therein at "[0 toward I the rear end of the same.

Rollers ll, i2 at the forward lower and upper edges respectively of the flap are positioned to ride in tracks 8 and 9.

These rollers may be carried by suitable mounting brackets l3, M on the ends of the flap. The brackets l3 are shown as extended forwardly to project the front rollers H a distance in front of the leading edge of the flap, providing added leverage and control.

An actuating rod I5 is shown pivotally connected with the flap at Hi. This rod may be operated from a source of power such as a hydraulic ram, electric motor and jack screw or the like. While push rod operation has definite advantages, operation may be effected by cables or other means.

The tracks may be cast, forged or machined as integral portions of the mounting brackets or they may be fabricated in other ways.

To keep friction to a minimum, rollers are usually preferred for operating in the tracks but it is contemplated that sliding elements may be employed in place of rolling elements. This, to some extent, may be governed by the particular shapes of cam tracks employed.

While usually preferable to mount the tracks in the wing structure and the rollers or slides on the flap, it is possible that this relation be reversed with the rollers or slides on the wing structure and the tracks on the flap.

In the construction illustrated, when the actuating rod is extended from the Fig. l to the Fig. 2 position, the rollers will be forced to follow the paths of the two cam tracks and since these rollers are in fixed relationship, the fiap will be made to follow the composite of the two paths and to rotate through the angles determined by the design in the shape and location of the tracks. In the illustration the tracks are laid out on upwardly and downwardly faced intersecting flat arcs and these tracks being in somewhat overlapping relation, keeps the overall length of the track brackets all the loads may be taken out through the combi I I a nation of a couple on the rollers and compression or tension in the actuating means.

In the illustration the mechanism is shown as developed for an NACA slotted type flap but it may be applied to any slotted type flap, modified or full Fowler flap, or in fact, to anytype of flap or control surface requiring conditions :such as met in the combination disclosed.

Of particular importance is the fact that for a flap requiring the point about which it rotates to be outside the wing contours, all operations are accomplished with no projecting or external structure.

The plural tracks and rollers in the arrangement illustrated provide a compact operating structure,'taking up small space and one which can'be produced and installed at reasonably low cost.

What is claimed is:

High lift mechanism for aircraft comprising opposed end brackets having forward, upwardly concave, upwardly and rearwardly inclined cam tracks and rearward, downwardly concave cam tracks, starting above the rearward upper ends of the forward cam tracks and extendin rear- Wardly on downward incline therefrom, a high lift element provided with forward guide rollers at the forward lower dge of the same in engagement with the forward cam tracks and rearward guide rollers in rear of and above said forward guide rollers in engagement with said rearward cam tracks and a push rod connected with said high lift element at a point between said forward and rearward guide rollers for imparting fore and aft movement to said high lift element to thereby effect rolling extension and retraction movements of the same as determined wholly by said cam tracks.

. HAROLD W. EARHART.

REFERENCES CITED The following references are of record in the file of this patent: 

